Tightly coupling concept

package govind;

public class Topic {

           

            public void understand()

            {

                        System.out.println("Tight coupling concept");

            }

}

package govind;

public class Subject {

                        Topic t=new Topic();

                        public void startReading()

                        {

                                    t.understand();

                        }

                        public static void main(String[] args) {

                                    Subject s=new Subject();

                                    s.startReading();

                        }

                       

                                               

            }

o/p:----------

Tight coupling concept

Explanation: In the above program the Subject class is dependents on Topic class. In the above program Subject class is tightly coupled with Topic class it means if any change in the Topic class requires Subject class to change. For example, if Topic class understand() method change to gotit() method then you have to change the startReading() method will call gotit() method instead of calling understand() method.

                                                         loosely coupling concept

package govind;

public interface TopicInterface {

           

            public void understand();

}

package govind;

public class Topic1 implements TopicInterface {

            @Override

            public void understand() {

            System.out.println("understand");

                       

            }

}

package govind;

public class Topic2  implements TopicInterface{

            @Override

            public void understand() {

                        System.out.println("gotit");

                       

            }

}

package govind;

public class Sub {

            public static void main(String[] args) {

                        TopicInterface t1=new Topic1();

                        TopicInterface t2=new Topic2();

                        t1.understand();

                        t2.understand();

            }

}

o/p:-------------

understand

gotit

Explanation : In the above example, Topic1 and Topic2 objects are loosely coupled. It means TopicInterface is an interface and we can inject any of the implemented classes at run time and we can provide service to the end user.

Note:-----------

 In order to over come from the problems of tight coupling between objects, spring framework uses dependency injection mechanism with the help of POJO/POJI model and through dependency injection its possible to achieve loose coupling.

package govind;

public class Box {

            public double volume;

           

            public Box(double length,double width,double height)

            {

                        this.volume=length*width*height;

            }}

package govind;

public class Volume {

            public static void main(String[] args) {

                        Box b=new Box(5.0, 5.0, 5.0);

                        System.out.println(b.volume);

            }

}

Explanation:In the above example, there is a strong inter-dependency between both the classes. If there is any change in Box class then they reflects in the result of Class Volume.

package govind;

public final class Box1 {

           

            private double volume;

            public Box1(double length,double width,double height)

            {

                        this.volume=length*width*height;

            }

           

            public double getVolume()

            {

                        return volume;

            }}

package govind;

public class Volume1 {

            public static void main(String[] args) {

                        Box1 b=new Box1(5.0, 5.0, 5.0);

                        double d=b.getVolume();

                        System.out.println(d);

            }

}

Explanation : In the above program, there is no dependency between both the classes. If we change anything in the Box1 classes then we dont have to change anything in Volume1 class.